question_answer 51)

    A cylindrical conductor of length  and uniform area of crossection A has resistance R. Another conductor of length 21 and resistance R of the same material has area of cross-section. (a) A/2                  (b) 3A/2                               (c) 2A                    (d) 3A

Answer:

                  (c) In first case, Resistivity of the conductor,?(i) In second case, Resistivity of the conductor, ..?(ii) For same material, resistivity of the conductor will be same. So, on substituting the value of in Eq. (ii), we have